Very Very Mini Unix Tutorial

ls List current directory
ls <dir> List contents of directory <dir>
cd <dir> Go to directory <dir>
cd Go to home directory
pwd Print current directory
mkdir <dir> Create directory <dir>
cp <file> <dir> Copy file <file> to directory <dir>
emacs21 & Run Emacs editor
sml Run SML/NJ
There are a number of Unix tutorials for beginners online, for example this one (Google's first entry for "Unix tutorial").

Few things to know about Emacs

You can use the menus to do everything you need. Many common menus have shortcuts. For example, "Undo" is CTRL + "_" (control underscore), saving a file is CTRL + "x" "s" (control x s), and exiting Emacs is CTRL + "c" "c".

SML Starter

use "<file>"; Load file <file> into SML
reset; Resets SML
CTRL + "D" Exit SML
Read this tutorial for more.
Iliano Cervesato